Effect Of Cushion Layer On Dynamic Characteristics Of Hydropower House

Recent years, with the development of the hydro-electrical enterprise in China, the unit capacity of the hydropower station is larger, and the stability of the hydraulic turbine is more important. The spiral case is the main part of hydropower station, becausing of steel plate and concrete have a soft cushion to save greatly in structure of spiral case, which make function of restriction to steel shell, may cause the disadvantageous influence when unit is running. In the past, static analysis once did a great deal of research about structure of powerhouse using cushion, study about motive characteristic of the structure of powerhouse with the variety of cushion parameters need to further investigate in engineer.Therefore, this paper unifies the project of the Laxiwa hydropower station, does some studies on the structure of powerhouse using cushion layer based on finite element method ANSYS.(1)Take a middle criteria unit to establish the powerhouse by the three dimensional finite element model, which includes generator floor slab, busbar floor slab, wind cover, etc. The effects of elastic modulus, overlook angle and extent to fag end of cushion layer on the natural vibration of the powerhouse structure are studied separately, obtained the natural regularity of powerhouse structure under the soft cushion.(2)Compute the natural frequency of powerhouse structure and analysis vibrancy source of hydraulic turbine set, estimate the possibility of resonance between powerhouse and turbine, the structure design of powerhouse is generally reasonable if there is not possibility that the resonance happens.(3)The dynamic characteristic of the powerhouse has been analyzed based on the different cushion:the stress and deformation of the powerhouse structure are studied under the vibrational loads of units, and obtained the vibration regulation of the powerhouse.(4)On the basis of the measured pulsating pressure data obtained from hydraulic turbine model test, the harmonic analysis method and the transient analysis method were proposed to study the vibration responses of the structure, obtained the vibration regularity under the variety of elastic modulus, overlook angle and extent to fag end of cushion layer. The results showed that the vibration responses of the powerhouse structure has the same regulation.During the modeling and calculating, the simulation of structure is as accurate as possible to reflect the characteristic of real engineering. The dynamic characteristics of powerhouse structure with the variety of cushion parameters is mainly studied in the paper, as a result, some useful conclusions has the reference value in projects.